Venturi type cylinder head



Feb. 11, 1936. c. E. SUMMERS 2,030,663

VENTURI TYPE CYLINDER HEAD Filed Feb. 20, 1953 Patented Feb. 11, 19 36 UNITED STATES PAl EN'l" OFFICE v 2,030,863 VENTURI TYPE CYLINDER HEAD Caleb E. Summers, Pontiac, Mlcln, assignmto General Motors Corporation, Detroit, Mich, a corporation of Delaware Application February 20, 1933, Serial No. 657,824

. 6 Claims. (01.123-191) introduce cooled walls to reduce the temperature of the compressed charge and also to influence thedirection of currents and the rate of burn v of the combustible charge; to fill up the dead space in the combustion chamberwith water cooled iron thereby giving more room along the normal flow paths of the gases; and by the-combination oi these advantages to enable the use of' higher compression without detonation and therefore obtain greater power and economy with smooth engine. operation.

' To accomplish the objects of the invention the combustible chamber is formed by providing a boss or projection'which extends from the water 2!! jacket of the cylinder head inwardly or the combustion chamber over the exhaust valve to give a flat water cooled surface closely adjacent the exhaust valve'whe'n in open position. -The application-of such a boss reduces the amount of combustible gas over the exhaust valve *when in closed position'and accordingly reduces the valume of gas heated. There is therefore obtained the double advantageof reducing the temperature ofthe exhaust valve and abo reducing the volume classes subjected to its temperature. The boss. or projection-lose shaped that when the exhaust.

valveis iii fully opened position the valve and boss will form continuations of each" other to give smooth ilow lines for the exhaust gases. A

By the provision of the boss or projection in the combustion chamber over the exhaust valve the volume'of the chamber is reduced which will allow a corresponding increase in volume over theinlet valve where it is desired and wm allow an easier inflow of fuel mixture. The volume'of the combustion chamber due to the provision oi the boss can be so proportioned that an increased compression ratio is obtained without changing o the .other structure or characteristics of the engine.

The invention is disclosedon the accompanying drawing in which: v 1

Figure 1 isa sectional view through one cylin- 55 der and the-head of a multi-cyiinder-internal combustion engine, the section beingtaken through the exhaust valve. Figure 2 is a bottom plan view of the cylinder head showing combustion chambers and taken on the line 2--2 of Figure 1. 5 Figures 3 and 4 are sections taken on the lines 3-3 and 4-4 of Figure 2. 1 Figure 5 is a vertical sectional view parallelto the valve stems through thetop of one cylinder showing a modified form of my invention. 1

On the drawing, the numeral 2 indicates an internal combustion engine as a whole. The engine has a plurality of cylinders, one of which is indicated at 4 and in each of which there operates a piston I connected in the usual manner to a g connecting rod by the wrist pin. 8. The engine has the usual water jacket for the cooling sys-' tem of the. engine. Suitable sleeves I! mounted in the engine block receive the stems of the exhaustyalves It, the heads of whichare indi- 2 cated at l8. "The cylinder block is formed with the usual valve seats 20 to cooperate with the seats 22 on the valve heads l8. r The cylinder head is indicated at 24 and is connected to the main cylinder block by means of 25 bolts 26 and nuts 18,-9, gasket 30 being interposed between the head and the block. The water circulatingsystem' ll is'connected by means of a plurality of passages 32 and 34 with the water jacket 36 of the cylinder head 24. 30 The parts so far described are conventional and per se form no part of the invention. a The novel [combustion chamber of the invention is indicated as a whole at 38. 'The upper wall 40 of the combustion chamber likewise forms '35- one wall of the water jacket 36. and a boss or projection 42 extends downwardly from the water jacket and inwardly of the combustion chamber and over the head it of the exhaust valve It. The bottom of thewboss 42 is substantially flat 40 and is in'very close proximity of the head it of the exhaust valve when the latter is in open posi tion as shown in Figure 1. This position leaves but a very thin or small space 44; between the valve. head is and the projection 42 and correover'the exhaust valvein open position has been greatly reduced which correspondingly reduces the volume of the hot exhaust gases thereover when the valve is in the closed position. n:

2. spark plug openings 41 are positioned close to the b088'42'so the spark plug points will be close to the small 'volume of relatively hot gases over the the valve seat 22, and the conical continuation "49 of the valve head 'form smooth flow lines which will aid the exhaust gases in passing from the combustion chamber 38. If the boss were not present there would be the large space between the dotted line 48 and the top of the head I! which would disturb the smooth fiow of-gases throughthe exhaust valve opening and leave a much larger amount of exhaust gas to heat the valve. The presence of the boss and the provision of the smooth lines at the sides of the boss and on the valve greatly aid the exhaust gases in leaving the combustion chamber. The exhaust gases are deflected by the boss 42 so that a smooth flow curve is established as the gases leave the valveopenings This reduces back pressme and permits a more thorough scavenging of the combustion chamber and prevents the fire from im-.- pinging directly on, the valve. During the period when the exhaust valve is near wide open position the proximity of its heated head I! to the relatively .cool boss 42 reduces the temperature of the valve. Even when the valve head I! is on its seat the distance from the top of the'head to the water cooled surface ofthe boss 42 is only approximately half as great as in the conventional combustion chamber.

The temperature of the gases in the combution chamber 38 just before ignition varies with their proximity to heated surfaces. The importance of this temperature is again dependent on the volume of gases so heated. The volume of gas above the exhaust valve head I8 is reduced to approximately half the normal volume, therefore its importance as an area of rapid flame travel is accordingly diminished. There is'thereiore the I double advantage of reducing the temperature of the exhaust valve and also reducing the volume of gases subjected to its temperature.

In a high compression motor, particularly of 4 short stroke, the volume of the combustion chamber becomes small and where through nty its area must be considerably extended to provide ample space for valves, etc., the

' chamber becomes 'too thin to aflord ample passage'for the gases from the inlet valve and to the exhaust valve. In the structure above the practically dead space above the exhaust valve which has little value as a 'e for gases is filled with metal.; In addition to having the cooling and air flow advantages previously mentioned, there is a reduction in the total volume of the combustion chamber. so additional volume can be applied at points where it is required. Thus, by filling the dead space above the exhaust valve it is possible to lift the space above the inlet valve, giving room for the incoming gases to flow around-and over the inlet valve with minimum obstruction.

The location of a boss projecting from the water cooled metal of the cylinder head in a place where it is'in itself beneficial has the further advantage of changing the shape of the combustion chamber and breaking up the long straight lines which bring about too rapid flame propagation. The location for the spark plug is also-chosen so it is near the small volume of relatively hot gas over the exhaust valve so this fore. An inlet valve head 50 is located adjacent the exhaust valve and has aprojection-42' extending down toward the valve from the head 24 in exactly the same manner. Such a cylinder head havingthe twd bosses in each combustion chamber has been built and used, but in the particular design of the motor desired to be used at the time, this second boss over the inlet valve was found not to be necessary. The second boss, however, is fundamentally an essential part of the structure of the invention which is to provide a streamline passage for the fiow of gas to and from the combustion chamber.

In ordinary practice where the conventional type of combustion chamber is used having an appreciable space between the tops of the valves in open position and the top of the. combustion chamber the flow out from or into the combustion chamber entails. an abrupt change in direction of the flow and the sacrifice of practically all the energy represented by the inertia of the gases. The application of this streamlining structure to the combustion chamber over the inlet valve is more important insofar as increasing the volumetric emciency of the motor is concerned than is the streamlining of the exhaust valve.

A practical need for a structure which involves the use of hoses over both the inlet and exhaust valves is appearing in the presiiit state of the internal combustion engine art. Experiments conducted along the lines of disclosure of the inventionhave disclosed that it is difilcult with L headengines to reducethe volume of the combustion chamber to obtain the high compression ratio needed "for ethyl gasoline when the valves are amply spaced to facilitate cooling of the engine block. By eliminating thewaste space over the topsflof the valves it increases available space for the flow of gas to and from the valve.

In applying a boss 42 over the inlet valve the bossisconstructed similarlytotheboss 42 over the exhaust valve, or if desired, the tw tegral or elongated boss. I claim: 1

1. In an internal combustion inlet and exhaust valves and a combustion cham-.

her, said engine having a jacketed cooling system,

a non-recessed solid bo'ss extending from the cooling system into the combustion'chamber over the exhaust valve, said boss having a substantially round fiat surface in close proximity to the valve when the latter is in open position. .7

2. In an internal combustion engine having inlet and exhaust valves and a combustion chain ber,- said engine having a jacketed cooling system, a boss extending from the cooling system into the combustion chamber over the exhaust valve, said boss beingin close proximity to the valve engine having when the latter is in open position, the side of said valve in its open position forming substantially:a continuation of the side of the bow to form a smooth surface 1hr the outflow of gases.

3.,Infan internal combustion engine having a cooling system, inlet and exhaust valves, anda combustion chamber, a boss or projection extendin mm the coolin system into the combustion is chamber to form a cooling surface closely adjacent the exhaust val said exhaust valve in open position, extending very close to the projection, the sides of said exhaust valve in its open position forming a substantial continuation of the sides 01' the projection to give a smooth flow or stream line construction within the combustion chamber to facilitate the outflow of exhaust gases, and a smooth surface free of projections over the remainder of the extent '0'! the combustion chamber. V

4. In an internal combustion engine having a cooling system, inlet and outlet valves, and a combustion chamber, a solid boss projecting from the cooling system into the combustion chamber and positioned in a place not actively used for the transfer oi. gases, said boss facilitating the outflow of exhaust gasestrom the chamber and reducing the combustion chamber space.

5. In an internal combustion engine having a cooling system, inletand outlet valves, and a combustion chamber,

a boss projecting from the 3 cooling system into the combustion chamber and positioned in very close proximity to the outlet valve when said valve is .in open positiomsaid exhaust valve in open position forming a'substantial continuation of said boss to form a substantially smooth stream line part for the flow oi exhaust gases, the remainder of said combustion chamber being substantially smooth and tree from obstructions, said boss decreasing the volume of the combustion chamber to cause an increase in the compression ratio.

6. In an internal combustion engine having inlet and exhaust valves and a combustion chamber, said engine having a jacketed cooling system, a solid boss extending from the cooling system into the combusticm chamber over the exhaust valve, a separate second solid boss extending from the cooling system into the combustion chamber over the inlet valve, said bo'sses being in close proximity to the valves when the latter are in open position. CALEB E. SUMMERS. 

